The invention relates to a method for production of deep p regions in silicon, and to semiconductor components produced using the method.
In the production of semiconductor components, there is frequently a wish to produce a p-doped zone which extends deep into the semiconductor component and which can be used as previously normal isolating diffusion or else for specific edge terminations, which penetrate into the depth, of the pn junction (see, for example, DE 102 40 107.1 A (not yet published) from Infineon Technologies AG). In the past, such dopings extending deep into the semiconductor were produced either by diffusion processes lasting for a very long time and at very high temperatures, or by a combination of trench production with subsequent side-wall doping.
In the case of semiconductor components such as IGBTs, diodes and thyristors, an anode emitter with low emitter efficiency is frequently desired, which at the same time makes a good resistive contact with the contact metal and in which process-dependent inhomogeneities, such as particles on the wafer surface during the ion implantation process, have no disadvantageous effects on the electrical characteristics of the components containing this p emitter.
A p emitter with low emitter efficiency has in the past been produced by, for example, a so-called transparent emitter being used, which not only has relatively light doping but in which the penetration depth of the dopant is shallow, particularly for IGBTs. This technique has, however, also already been adopted for diodes, in which case this approach has been found to be problematic in the case of diodes, in which the p emitter at the same time forms the reverse-biased pn junction, due to the lack of any capability to provide an effective edge termination for the pn junction formed in this way. Particularly in the case of transparent emitters, undesirable lateral inhomogeneities in the p-doped emitter can occur as a result of particles which are located on the wafer surface during the ion implantation. In order to overcome this, the so-called “ana” (German language abbreviation for healed/not healed) emitter was proposed, although this requires additional high-temperature process steps.
One object of the invention is therefore to specify a method for production of deep p regions in silicon, which avoids very long diffusions at very high temperatures or else trench production with subsequent side-wall doping, and to use this method to produce p-doped emitters with low emitter efficiency for semiconductor components such that a good resistive contact with the contact metal is also achieved, and such that process-dependent inhomogeneities have no disadvantageous effects on the electrical characteristics of the components which contain this p emitter or this anode.
This object is achieved according to the claims.